• Journal of Applied Reliability
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• v.13 no.4
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• pp.287-298
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• 2013

This paper presents a case study of PSD(Platform Screen Door) system assurance based on EN50126 life-cycle stage. By applying this system assurance, the accidents related to urban light transit railway especially that caused casualties could be reduced tremendously. This case study contributes significantly to the reliability, availability, maintainability and safety of the PSD system. Request For Proposal (RFP) of a rail road operator in which required by RAMS is prepared in which to ensure all system assurance activity and safety assessment are compulsory. The step-by-step activities and related deliverables are used which include functional analysis, FMECA, hazard identification analysis, system hazard analysis, maintainability analysis, FRACAS, and finally verification and validation of the system.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.52-59
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• 2016

Environmental Qualification has been almost developed except those of Non-Material Sub-components for valves and pumps though the time has only passed about 10years since EQ test launch of Korea. However EQ test has been performed by a few of engineers under the conditions that experience of EQ test is insufficient and EQ system is not developed completely. In recent years, Strengthen Nuclear Safety Regulation is being done Strictly Nuclear safety components Verification Procedure for Non-Material Sub-components, but the reports contain only performance test results, not Enviro nmental test methods relating to real Aging Degradation. In this Study, there were developed to performance systematically research to acquire EQ technology for five specimens of the Non-Material Sub-components in the Nuclear Power Plant.

• Journal of the Korea Construction Safety Engineering Association
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• s.47
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• pp.56-62
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• 2008

In order to apply the Limit Equilibrium Method generally used for the slope stability analysis to the vertical excavation walls reinforced by soil-nailing, in this study, the Limit Equilibrium Method for the temporary shoring facilities reinforced by soil-nailing was proposed, which is based on the stability for the horizontal displacement. In this study, the relation of the internal friction angles of the ground and the vertical excavation depths was arranged, which is satisfying the stability on the horizontal displacement by using the verification of the Limit Equilibrium Method. And then, the rational reinforcing length of soil-nailing was proposed for the critical areas. In addition, the modified safety ratio satisfying the stability on the horizontal displacement was proposed, when the Limit Equilibrium Method was applied to the vertical excavation walls reinforced by soil-nailing.

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.91-99
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• 2006

The diesel Auxiliary Power Unit (APU) for vehicle applications is a complex nonlinear system. For the purpose of this paper presents a dynamic average model of the whole system in an entirely physical way, which accounts for the non-ideal behavior of the diode rectifier, the nonlinear phenomena of generator-rectifier set in an elegant way, and also the dynamics of the dc load and diesel engine. Simulation results show the accuracy of the model. Based on the average model, a simple PI control scheme is proposed for the multivariable system, which includes the steps of model linearization, separate PI controller design with robust tuning rules, stability verification of the overall system by considering it as an uncertain one. Finally it is tested on a detailed switching model and good performances are shown for both set-point following and disturbance rejection.

• Journal of the Korean Society of Safety
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• v.11 no.2
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• pp.122-127
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• 1996

The purpose of this study has been studied and investigated to prediction algorithms of the Kalman Filtering theory which are based on the state-vector description, including system identification, model structure determination, parameter estimation. And the prediction algorithms applied of rainfall-runoff process, has been worked out. The analysis of runoff process and runoff prediction algorithms of the river-basin established, for the verification of prediction algorithms by the Kalman Filtering theory, the observed historical data of the hourly rainfall and streamflows were used for the algorithms. In consisted of the above, Kalman Filtering rainfall-runoff model applied and analysised to Wi-Stream basin in Nak-dong River(Basin area : $472.53km^2$).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.885-891
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• 2011

In this paper, we studied dc leakage current properties analysis of LED lamps of road and landscape lighting when leakage current appeared in dc power line. Generally, converter of LED lighting is divides to insulated type and non-insulated type according to components. When electric leakage happened in AC power line, earth leakage breaker(ELB) senses leakage current and interrupts electric circuit. In dc power source, We need experimental verification about dc electric leakage for electricity safety. In normal wiring conditions and in the water, in case of using insulated type of converter, dc leakage current did not occur. However, in case of using non-insulated type of converter, dc leakage current occurred and passed through into the ground. We found that there is a hazard of electric shock by dc leakage current. We expect that the results of these studies would be helpful for electrical safety of LED lamps for road and landscape lighting.

• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.404-418
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• 2016

This paper presents a documentation and development method to facilitate the certification of scientific computing software used in the safety analysis of nuclear facilities. To study the problems faced during quality assurance and certification activities, a case study was performed on legacy software used for thermal analysis of a fuelpin in a nuclear reactor. Although no errors were uncovered in the code, 27 issues of incompleteness and inconsistency were found with the documentation. This work proposes that software documentation follow a rational process, which includes a software requirements specification following a template that is reusable, maintainable, and understandable. To develop the design and implementation, this paper suggests literate programming as an alternative to traditional structured programming. Literate programming allows for documenting of numerical algorithms and code together in what is termed the literate programmer's manual. This manual is developed with explicit traceability to the software requirements specification. The traceability between the theory, numerical algorithms, and implementation facilitates achieving completeness and consistency, as well as simplifies the process of verification and the associated certification.

• International journal of advanced smart convergence
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• v.11 no.3
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• pp.56-63
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• 2022

Cyber-physical systems (CPSs) can solve real problems by utilizing closely connected resources in the cyber world. Most problems arise because the physical world is uncertain and unpredictable. To address this uncertainty, information pouring from numerous devices must be collected in real-time, and each interconnected device must share the information. At this time, CPS must meet timing-related techniques and strict timing constraints that can deliver accurate information within predefined deadlines in order to interact closely beyond simply connecting the cyber and physical worlds. Timing errors in safety-critical systems, such as automobiles, aviation, and medical systems, can lead to catastrophic disasters. In this paper, we classify timing problems into two types: real-time delay and synchronization problems. The results of this study can be used in the entire process of CPS system design, implementation, operation, verification, and maintenance. As a result, it can contribute to securing the safety and reliability of CPS.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.266-272
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• 2022

Structural stress analysis is performed to confirm the safety of the structures before the construction, and stress analysis is performed to evaluate the safety of various components before the ship or vehicle corresponding to the moving structure is manufactured. In this case, the stress analysis work is performed using the stress analysis software of each company. The results of the stress analysis based on the boundary conditions of the applied loads are analyzed to evaluate the safety of the structure, but the results are difficult to verify because most of the stress analysis software possessed by each company is one. In this paper, we were performed the stress analysis of the bracket applied to the bare chassis of the 30-passenger bus under development is performed by HYPERMESH. In order to verify this, the stress analysis is performed using ANSA/META under the same boundary condition. The stress analysis results of ANSA/META and HYPERMESH showed that they had the same stress distribution and the maximum stress occurred at the same location. Taken together, the results of stress analysis using HYPERMESH were reliable.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.54-55
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• 2021

This study compared the fire safety standards for windows of Korea, the U.S. and Japan to prevent fire expansion through exterior wall openings, and conducted experiments using PVC and aluminum window frames, which are widely used in Korea.The experiment is KS F 2845 which combines frames of the same thickness and area with single-window form and 1 hour fire resistance glass with 8T thickness. Experiments showed that the PVC window was about 9 minutes and the aluminum window was about 26 minutes. However, in Korea, there are no test standards for windows installed at the opening of the exterior wall. In addition, fire safety standards for windows shall be established along with the designation of fire prevention zones.